Platelet-shaped pigments

ABSTRACT

The present invention relates to platelet-shaped pigments comprising (a) a layer obtained by calcination of a layer comprising SiO z  wherein 0.03≦z≦2.0 and a metal, to a process for the production thereof, and to the use thereof in paints, text ink-jet printing, cosmetics, coating compositions, plastics, printing inks and in glazes for ceramics and glass. The aforementioned process makes available platelet-shaped pigments having a high degree of planeparallelism and a defined thickness in the range of ±10%, preferably ±5%, of the average thickness.

The present invention relates to platelet-shaped pigments comprising (a)a layer obtained by calcination of a layer comprising SiO_(z) wherein0.03≦z≦2.0 and a metal, to a process for the production thereof, and tothe use thereof in paints, textiles, ink-jet printing, cosmetics,coating compositions, plastics, printing inks and in glazes for ceramicsand glass. The afore-mentioned process makes available platelet-shapedpigments having a high degree of plane-parallelism and a definedthickness in the range of ±10%, preferably ±5%, of the averagethickness.

WO93/19131 disclose platelet-shaped colored pigments containing titaniumdioxide, one or more suboxides of titanium and an oxide or oxides of oneor more metals other than titanium or non-metals, wherein theconcentration of the titanium oxides in the coating layer is maximum inthe proxity of the substrate surface and gradually decreases toward thepigment surface.

WO00/34395, WO00/69975 and WO02/31058 describe bright metal flakes,SiO_(y1)/Al/SiO_(y1), wherein y1 is from about 1 to about 2. Thethickness of the aluminium layer is at least about 40 nm and thethickness of the SiO_(y1) layer is at least 10 nm.

WO03/68868 describes a process for producing SiO_(y) flakes. The SiO_(y)flakes may be treated with a carbon-containing gas at from 500 to 1500°C., preferably from 500 to 1000° C., preferably with the exclusion ofoxygen, wherein a SiC layer is formed on the SiO_(y) flakes.Alternatively the SiO_(y) flakes can be converted in SiO₂ flakes byheating them in an oxygen-containing atmosphere. The SiO₂ flakes can beused as substrates for interference pigments.

PCT/EP03/09296 discloses platelet-shaped pigments comprising a layerobtained by calcining TiO₂/SiO_(z), wherein 0.03≦z≦2.0, and their use inpaints, textiles, ink-jet printing, cosmetics, coatings, plasticsmaterials, printing inks, in glazes for ceramics and glass, and insecurity printing.

EP-A-803549 discloses colored pigments containing (a) a core consistingof an essentially transparent or metallic reflecting material, and (b)at least a coating consisting essentially of one or more siliconeoxides, the molar ratio of oxygen to a silicon being 0.25 to 0.95.

The present invention relates to platelet-shaped pigments, the particlesof which generally have a length of from 2 μm to 5 mm, a width of from 2μm to 2 mm and a thickness of from 20 nm to 1.5 μm and also a ratio oflength to thickness of at least 2:1, comprising (a) a layer obtained bycalcination of a layer comprising SiO_(z) wherein 0.03≦z≦2.0 and ametal.

The calcination is preferably conducted in a non-oxidizing atmosphere ata temperature above 600° C.

The particles of the platelet-shaped pigments generally have a length offrom 2 μm to 5 mm, a width of from 2 μm to 2 mm and a thickness of from20 nm to 1.5 μm and a ratio of length to thickness of at least 2:1,preferably at least 6.5:1, especially from 50:1 to 500:1. The particleshave two substantially parallel faces, the distance between which is theshortest axis of the core. The pigments (flakes) are not of a uniformshape. Nevertheless, for purposes of brevity, the flakes will bereferred to as having a “diameter.” The flakes have a highplane-parallelism and a defined thickness in the range of ±10%,especially ±5% of the average thickness. The flakes have a thickness offrom 20 to 2000 nm, very especially from 100 to 350 nm. It is presentlypreferred that the diameter of the flakes be in a preferred range ofabout 1-60 μm with a more preferred range of about 5-40 μm. Thus, theaspect ratio of the flakes of the present invention is in a preferredrange of about 14 to 400.

The platelet-shaped particles can be produced by means of a processcomprising

a) vapor-deposition of a separating agent layer onto a carrier,

b) then, simultaneous vapor-deposition of a metal and SiO_(z) wherein0.03≦z≦2.0 onto the separating agent layer,

c) dissolution of the separating agent in a solvent,

d) separation of the product from the solvent and

e) calcination of the product in a non-oxidising atmosphere.

Furthermore, the present invention relates also to the platelet-shapedparticles obtainable by that process.

The novel pigments can be used especially in automotive finishes,industrial coating compositions, plastics, printing inks and cosmeticformulations.

The pigment particles preferably have lengths and widths of from 5 to 50μm, especially from 5 to 25 μm, and a thickness of from 60 nm to 1.0 μm.

SiO_(z) wherein 0.03≦z≦2.0 means that the molar ratio of oxygen tosilicon is, on average, from 0.03 to 2.0.

Accordingly, SiO_(y) wherein 0.70≦y≦1.80 means that the molar ratio ofoxygen to silicon is, on average, from 0.70 to 1.80.

According to the present invention the term a layer comprising SiO_(z)and a metal means a composite layer of a matrix of SiO_(z) and embeddedtherein the metal, but is not intended to comprise multi-layerstructures of distinct layers of SiO_(z) and Al, such asSiO_(z)/Al/SiO_(z).

The metal of layer (a) can be, in principal, any metal that at thecalcining step reacts with SiO_(z), Al, Cu, Mo, V, Ag, Cr, Zr, Nb, Ni,Fe, Co, Ti or alloys thereof, such as chromium-nickel, iron-nickel,iron-chromium and nickel-cobalt, are preferred, wherein Al is mostpreferred.

According to the present invention the term “aluminium” comprisesaluminium and alloys of aluminium. Alloys of aluminium are, for exampledescribed in G. Wassermann in Ullmanns Enzyklopädie der IndustriellenChemie, 4. Auflage, Verlag Chemie, Weinheim, Band 7, S. 281 to 292.Especially suitable are the corrosion stable aluminium alloys describedon page 10 to 12 of WO00/12634, which comprise besides of aluminiumsilicon, magnesium, manganese, copper, zinc, nickel, vanadium, lead,antimony, tin, cadmium, bismuth, titanium, chromium and/or iron inamounts of less than 20% by weight, preferably less than 10% by weight.

The thickness of the mixed layer is dependent upon the metal used. Inthe case of co-sublimation of aluminium and SiO_(z) (z=from 0.03 to 2),where the mixed layer of aluminium and SiO_(z) forms the core of aninterference pigment on which further layers of metal oxides aredeposited, the thickness is generally from 5 to 100 nm, preferably from30 to 60 nm.

Layer (a) preferably forms the core of the pigment. Further layers maybe located on only one parallel surface of the core. Preferably,however, the further layers are arranged symmetrically about the core.Platelet-shaped structures which consist solely of a layer obtained bycalcination of a layer comprising SiO_(z) wherein 0.03≦z≦2.0 and ametal, especially aluminium, are especially suitable as substrates forinterference pigments and form a preferred embodiment (A) of the presentinvention.

A further subject of the present invention is the use of the pigments inink-jet printing (PCT/EP03/11189), for dyeing textiles (PCT/EP03/11188),for pigmenting coatings, printing inks, plastics, cosmetics(PCT/EP03/09296), glazes for ceramics and glass and in securityprinting.

In a preferred embodiment (B), the platelet-shaped pigment comprises

(b1) an SiO_(z) layer,

(a) a layer obtained by calcination of a layer comprising SiO_(z) and ametal, especially aluminium, and

(b2) an SiO_(z) layer, wherein 0.03≦z≦2.0.

In this embodiment the layer (a) preferably forms the core of thepigment, wherein the layers (b1) and (b2) are only present on theparallel faces of the core.

The thickness of the SiO_(z) layer is dependent upon the desired colorbut is generally from 10 to 1000 nm. A thickness of more than 500 nmresults in matt colors.

In one preferred embodiment of the present invention, the interferencepigments comprise materials having a “high” index of refraction, whichis defined herein as an index of refraction of greater than about 1.65,and optionally materials having a “low” index of refraction, which isdefined herein as an index of refraction of about 1.65 or less. Various(dielectric) materials that can be utilized include inorganic materialssuch as metal oxides, metal suboxides, metal fluorides, metaloxyhalides, metal sulfides, metal chalcogenides, metal nitrides, metaloxynitrides, metal carbides, combinations thereof, and the like, as wellas organic dielectric materials. These materials are readily availableand easily applied by physical, or chemical vapor deposition processes,or by wet chemical coating processes.

Examples of dielectric materials having a “high” index of refraction arezinc sulfide (ZnS), zinc oxide (ZnO), zirconium oxide (ZrO₂), titaniumdioxide (TiO₂), carbon, indium oxide (In₂O₃), indium tin oxide (ITO),tantalum pentoxide (Ta₂O₅), chromium oxide (Cr₂O₃), cerium oxide (CeO₂),yttrium oxide (Y₂O₃), europium oxide (Eu₂O₃), iron oxides such asiron(II)/iron(III) oxide (Fe₃O₄) and iron(III) oxide (Fe₂O₃), hafniumnitride (HfN), hafnium carbide (HfC), hafnium oxide (HfO₂), lanthanumoxide (La₂O₃), magnesium oxide (MgO), neodymium oxide (Nd₂O₃),praseodymium oxide (Pr₆O₁₁), samarium oxide (Sm₂O₃), antimony trioxide(Sb₂O₃), silicon monoxides (SiO), selenium trioxide (Se₂O₃), tin oxide(SnO₂), tungsten trioxide (WO₃), or combinations thereof. The dielectricmaterial is preferably a metal oxide. It being possible for the metaloxide to be a single oxide or a mixture of oxides, with or withoutabsorbing properties, for example, TiO₂, ZrO₂, Fe₂O₃, Fe₃O₄, Cr₂O₃, irontitanate, iron oxide hydrates, titanium suboxides, or ZnO, with TiO₂being especially preferred.

It is possible to obtain pigments that are more intense in color andmore transparent by applying, on top of the layer of the dielectricmaterial having a “high” index of refraction, especially a TiO₂ layer, ametal oxide of low refractive index. Nonlimiting examples of suitablelow index dielectric materials that can be used include silicon dioxide(SiO₂), aluminum oxide (Al₂O₃), and metal fluorides such as magnesiumfluoride (MgF₂), aluminum fluoride (AlF₃), cerium fluoride (CeF₃),lanthanum fluoride (LaF₃), sodium aluminum fluorides (e.g., Na₃AlF₆ orNa₅Al₃F₁₄), neodymium fluoride (NdF₃), samarium fluoride (SmF₃), bariumfluoride (BaF₂), calcium fluoride (CaF₂), lithium fluoride (LiF),combinations thereof, or any other low index material having an index ofrefraction of about 1.65 or less. For example, organic monomers andpolymers can be utilized as low index materials, including dienes oralkenes such as acrylates (e.g., methacrylate), polymers ofperfluoroalkenes, polytetrafluoroethylene (TEFLON), polymers offluorinated ethylene propylene (FEP), parylene, p-xylene, combinationsthereof, and the like. Additionally, the foregoing materials includeevaporated, condensed and cross-linked transparent acrylate layers,which may be deposited by methods described in U.S. Pat. No. 5,877,895,the disclosure of which is incorporated herein by reference. SiO₂,Al₂O₃, AlOOH, B₂O₃, or a mixture thereof, are preferred. SiO₂ is mostpreferred.

Especially preferred interference pigments based on embodiment (A) or(B) furthermore comprise, preferably over the entire surface of thepigment, a metal oxide of high refractive index, especially TiO₂ orFe₂O₃, and, optionally, additionally on the layer of the metal oxide ofhigh refractive index, a metal oxide, especially SiO₂, of low refractiveindex.

Accordingly, the present invention relates also to platelet-shapedpigments comprising

(c1) a layer of a metal oxide of high refractive index, especially TiO₂or Fe₂O₃,

(b1) optionally, an SiO_(z) layer,

(a) a layer obtained by calcination of a layer comprising SiO_(z) and ametal,

(b2) optionally, an SiO_(z) layer, wherein 0.03≦z≦2.0, and (c2) a layerof a metal oxide of high refractive index, especially TiO₂ or Fe₂O₃.

In this embodiment the layer (a) preferably forms the core of thepigment, wherein (b1) and (b2) are preferably only present on theparallel faces of the core. The layer (c1) and (c2) of the material ofhigh refractive index, especially TiO₂, can be present only on layers(c1) and (c2), but is preferably present on the whole surface of thepigment.

The metal oxide of high refractive index is preferably selected fromTiO₂, ZrO₂, Fe₂O₃, Fe₃O₄, Cr₂O₃, ZnO, and mixtures of those oxides, andan iron titanate, an iron oxide hydrate, a titanium suboxide, andmixtures or mixed phases of those compounds, especially Fe₂O₃ and TiO₂.The metal oxide of low refractive index is preferably selected fromSiO₂, Al₂O₃, AlOOH, B₂O₃ and mixtures thereof, it being possible,optionally, for alkali metal oxides or alkaline-earth metal oxides to bepresent as additional constituents.

The properties that can be achieved with the novel pigments comprising alayer obtained by calcination of a layer comprising SiO_(z) and a metal,especially aluminium, can be summarised as follows:

-   -   improved substrate properties        -   uniform substrate thickness which can be precisely            controlled,        -   smooth and uniform substrate surface,        -   transparent substrate without intrinsic color,    -   improved reflection and refraction of light,        -   improved color strength and color purity,        -   new color-changing effects.

Further preferred interference pigments which are based on embodiment(A) or (B) can be coated with one or more layers of metal or metalalloys, the metal or metal alloy being selected, for example, fromchromium, nickel, silver, bismuth, copper, tin and Hastelloy(nickel-base alloys), or with a metal sulfide, the latter being, forexample, a metal sulfide of tungsten, molybdenum, cerium, lanthanum orrare-earth metals.

When the further layers are layers of metal or metal alloys, thethickness of the core may be from 10 to 1000 nm, depending on the metalused and the desired color, and is preferably less than 500 nm. Thefurther layers may be applied by wet chemical means or by PVD or CVDmethods.

Interference pigments based on embodiment (A) or (B) and, optionally,coated by wet chemical means, in the order stated, with TiO₂ (core:SiO_(z)/Al; layer: TiO₂), (SnO₂)TiO₂, Fe₂O₃, Fe₂O₃·TiO₂ (core:SiO_(z)/Al; layer mixed layer of Fe₂O₃ and TiO₂), TiO₂/Fe₂O₃ (coreSiO_(z)/Al; first layer: TiO₂; second layer: Fe₂O₃), TiO₂/Prussian Blue,TiO₂/Cr₂O₃, TiO₂/FeTiO₃, TiO₂/SiO₂/TiO₂, (SnO₂)TiO₂/SiO₂/TiO₂,TiO₂/SiO₂/TiO₂/SiO₂/TiO₂ or TiO₂/SiO₂/Fe₂O₃ are especially preferred.

The TiO₂ may optionally be reduced by means of customary methods: U.S.Pat. No. 4,948,631 (NH₃, 750-850° C.), WO93/19131 (H₂, >900° C.) orDE-A-198 43 014 (solid reducing agent, for example silicon, >600° C.).

The metal oxide layers can be applied by CVD (chemical vapor deposition)or by wet chemical coating. The metal oxide layers can be obtained bydecomposition of metal carbonyls in the presence of water vapor(relatively low molecular weight metal oxides such as magnetite) or inthe presence of oxygen and, where appropriate, water vapor (e.g. nickeloxide and cobalt oxide). The metal oxide layers are especially appliedby means of oxidative gaseous phase decomposition of metal carbonyls(e.g. iron pentacarbonyl, chromium hexacarbonyl; EP-A-45 851), by meansof hydrolytic gaseous phase decomposition of metal alcoholates (e.g.titanium and zirconium tetra-n- and -iso-propanolate; DE-A-41 40 900) orof metal halides (e.g. titanium tetrachloride; EP-A-338 428), by meansof oxidative decomposition of organyl tin compounds (especially alkyltin compounds such as tetrabutyltin and tetramethyltin; DE-A-44 03 678)or by means of the gaseous phase hydrolysis of organyl silicon compounds(especially di-tert-butoxyacetoxysilane) described in EP-A-668 329, itbeing possible for the coating operation to be carried out in afluidised-bed reactor (EP-A-045 851 and EP-A-106 235). Al₂O₃ layers (B)can advantageously be obtained by controlled oxidation during thecooling of aluminium-coated pigments, which is otherwise carried outunder inert gas (DE-A-195 16 181).

Layers of oxides of the metals zirconium, titanium, iron and zinc, oxidehydrates of those metals, iron titanates, titanium suboxides or mixturesthereof are preferably applied by precipitation by a wet chemicalmethod, it being possible, where appropriate, for the metal oxides to bereduced. In the case of the wet chemical coating, the wet chemicalcoating methods developed for the production of pearlescent pigments maybe used; these are described, for example, in DE-A-14 67 468, DE-A-19 59988, DE-A-20 09 566, DE-A-22 14 545, DE-A-22 15 191, DE-A-22 44 298,DE-A-23 13 331, DE-A-25 22 572, DE-A-31 37 808, DE-A-31 37 809, DE-A-3151 343, DE-A-31 51 354, DE-A-31 51 355, DE-A-32 11 602 and DE-A-32 35017, DE 195 99 88, WO 93/08237, WO 98/53001 and WO03/6558.

The metal oxide of high refractive index is preferably TiO₂ and themetal oxide of low refractive index is preferably SiO₂. Layers of TiO₂can be in the rutile or anastase modification, wherein the rutilemodification is preferred. TiO₂ layers can also be reduced by knownmeans, for example ammonia, hydrogen, hydrocarbon vapor or mixturesthereof, or metal powders, as described in EP-A-735,114, DE-A-3433657,DE-A-4125134, EP-A-332071, EP-A-707,050 or WO93/19131.

For coating, the substrate particles are suspended in water or HCl andone or more hydrolysable metal salts are added thereto at a pH valuethat is suitable for hydrolysis and that is so selected that the metaloxides or metal oxide hydrates are precipitated directly onto theparticles without secondary precipitations occurring. The pH value canbe kept constant by simultaneous metering-in of a base. The pigments arethen separated off, washed and dried and, optionally, calcined, it beingpossible for the calcinating temperature to be optimised with respect tothe particular coating present. If desired, after the application ofindividual coatings, the pigments can be separated off, dried and,optionally, calcined, before being resuspended for precipitation of thefurther layers. The coating can furthermore also be carried out in afluidised-bed reactor by gas-phase coating, for which, for example, themethods proposed in EP-A-0 045 851 and EP-A-0 106 235 for the productionof pearlescent pigments can be used accordingly.

In the case of multi-layer pigments, the interference color isdetermined by the amplification of certain wavelengths and, when aplurality of layers in a multi-layered pigment have the same opticalthickness, the color of the reflected light becomes more intense andmore saturated the greater the number of layers. In addition, bysuitably selecting the layer thicknesses, an especially great variationin color depending on the viewing angle can be achieved. A pronouncedcolor flop is formed, which may be desirable for the pigments accordingto the invention. The thickness of the individual metal oxide layers,irrespective of their refractive index, is therefore from 20 to 500 nm,preferably from 50 to 300 nm.

For application of the titanium dioxide layers, preference is given tothe method described in U.S. Pat. No. 3,553,001.

An aqueous titanium salt solution is slowly added to a suspension of thematerial being coated, which suspension has been heated to approximately50-100° C., especially 70-80° C., and a substantially constant pH valueof approximately from 0.5 to 5, especially approximately from 1.5 to2.5, is maintained by simultaneous metering-in of a base, for exampleaqueous ammonia solution or aqueous alkali metal hydroxide solution. Assoon as the desired layer thickness of precipitated TiO₂ has beenachieved, the addition of titanium salt solution and base is stopped.That method, also referred to as a titration method, is distinguished bythe fact that an excess of titanium salt is avoided. That is achieved byfeeding in for hydrolysis, per unit of time, only that amount which isnecessary for even coating with the hydrated TiO₂ and which can be takenup per unit of time by the available surface of the particles beingcoated. Accordingly, hydrated titanium dioxide particles are not formedand not precipitated onto the surface being coated. The anastase form ofTiO₂ is obtained by that method. The rutile form of TiO₂ can be obtainedby depositing SnO₂ before depositing the TiO₂ layer and calcining thepigment at approximately from 700 to 900° C. It is also possible toprecipitate nano-TiO₂ of the rutile type having particle sizes of from 1to 50 nm by means of hydrolysis of TiCl₄ using hydrochloric acid attemperatures of from 0 to 60° C. (Lit: R. J. Nussbaumer, W. Caseri, T.Tervoort and P. Smith, Journal of Nanoparticle Research 2002, 4,319-323; Anpo et al. J. Phys. Chem. 1987, 91, 4305). It is likewisepossible to precipitate nano-TiO₂ of the anastase type having particlesizes of from 10 to 40 nm (crystallite size: <10 nm) by hydrolysis ofTi(OiPr)₄ (=titanium tetraisopropoxide) using water at from 0 to 50° C.and subsequently separating off the isopropanol formed, at temperaturesof from 50 to 100° C. and a slight vacuum (p about 200 torr) (Lit: K. I.Gnanasekar et al. Journal of Materials Research 2002, 17(6), 1507-1512).It is likewise possible for a solution of titanic acid, prepared fromTiCl₄ by hydrolysis using ammonium hydroxide and subsequent oxidationusing H₂O₂, to be added to an aqueous solution of the Al/SiO_(z) flakes;by heating at from 100 to 250° C. there are spontaneously formed fromthat solution nano-TiO₂ particles of the anastase type having particlessizes of about 10 nm (Lit: H. Ichinose, M. Terasaki and H. Katsuki,Journal of the Ceramic Society of Japan, Int. Edition 1996, 104(8),715-718). Such solutions and dispersions have now also becomecommercially available (Kon Corporation, 91-115 Miyano Yamauchi,Kishimagun Saga-prefecture, Japan 849-2305). The Al/SiO_(z) flakescoated with titanium, zirconium or iron can be subsequently coated withorganic or inorganic compounds by known methods.

For application of the silicon dioxide layers, the following method maybe used: a soda waterglass solution is metered in to a suspension of thematerial being coated, which suspension has been heated to approximatelyfrom 50 to 100° C., especially from 70 to 80° C.

The pH value is kept constant at from 4 to 10, preferably from 6.5 to8.5, by simultaneously adding 10% hydrochloric acid. After addition ofthe waterglass solution, stirring is carried out for a further 30minutes.

To enhance the weather and light stability the multilayer flakes can be,depending on the field of application, subjected to a surface treatment.Useful surface treatments are, for example, described in DE-C-2215191,DE-A-3151354, DE-A-3235017, DE-A-3334598, DE-A-4030727, EP-A-649886,WO97/29059, WO99/57204, and U.S. Pat. No. 5,759,255. Said surfacetreatment might also facilitate the handling of the pigment, especiallyits incorporation into various application media.

Furthermore, interference pigments based on embodiment (A) or (B) mayhave a thin semi-transparent metal layer on one parallel surface,preferably on both parallel surfaces. The metal layer is typically from5 to 25 nm thick and especially from 5 to 15 nm thick and consists of,for example, Cr, Ti, Mo, W, Al, Cu, Ag, Au, or Ni.

The semitransparent metal layer can be applied by PVD. Alternatively themetal layer can be obtained by wet chemical coating or by chemical vapordeposition, for example, gas phase deposition of metal carbonyls. Thesubstrate is suspended in an aqueous and/or organic solvent containingmedium in the presence of a metal compound and is deposited onto thesubstrate by addition of a reducing agent. The metal compound is, forexample, silver nitrate or nickel acetyl acetonate (WO03/37993).

According to U.S. Pat. No. 3,536,520 nickel chloride can be used asmetal compound and hypophosphite can be used as reducing agent.According to EP-A-353544 the following compounds can be used as reducingagents for the wet chemical coating: aldehydes (formaldehyde,acetaldehyde, benzalaldehyde), ketones (acetone), carboxylic acids andsalts thereof (tartaric acid, ascorbic acid), reductones (isoascorbicacid, triosereductone, reductic acid), and reducing sugars (glucose).

Calcination of the pigments includes calcination of the pigments in anon-oxidising gas atmosphere and, where appropriate, in anoxygen-containing atmosphere. Calcination of the pigments in anon-oxidising gas atmosphere, for example Ar and/or He, preferably Ar,is carried out at a temperature of more than 600° C., preferably in therange from 700 to 1100° C., for more than 10 minutes, preferably forseveral hours, where appropriate under reduced pressure, preferably lessthan 0.9333 10⁵ N/m² (700 torr). Calcination may be carried out aftercoating with the metal oxide of high refractive index but is preferablyperformed before coating with the metal oxide of high refractive index.

The platelet-shaped material may be produced in a multiplicity ofdifferentiable and reproducible variants by varying only two processparameters: the thickness of the vacuum coating of the mixed layer ofmetal and SiO_(z), and the proportion of metal embedded in the mixedlayer.

The mixed layer and the separating agent layer are applied byvapor-deposition, the metal being admixed with the SiO_(z) by means ofsimultaneous vaporization in vacuo. The ratio of metal, especiallyaluminium, to SiO_(z) is generally less than 60% by weight, preferablyless than or equal to 50% by weight. When Al and SiO_(z) are vaporizedsimultaneously, preference is given to conversion of all the aluminiuminto Al³⁺ by means of calcination:Al+(3/2z)Si²⁺→(3/2z)Si+Al³⁺

It is assumed, that by calcining of metal/SiO_(z) in a non-oxidizingatmosphere a composite layer is obtained, whereby a change of therefractive index is caused. It is assumed, that the change of therefractive index is based on the oxidation of the metal by SiO_(z). Itis, for example, known that by heating of SiO and aluminium at 650° C.Si and Al₂O₃ are formed and that by heating of SiO and titanium at 900°C. titanium silicides are formed (New J. Chem., 2001, 25, 994-998).

Production is especially simple when the mixed layer is produced by twovaporizers whose vapor jets overlap so that the mixed layer is producedin the overlapping region. As an alternative thereto, vaporization mayalso be carried out by means of a single vaporizer which vaporizes thetwo components simultaneously or alternately.

The materials are produced by means of vapor-deposition methods byheating and vaporizing the substances to be vaporized in vacuo in thepressure range from 1 to 10⁻³ Pa. The vapors condense on the coldsubstrate surfaces to form the desired thin layers.VaporizationVaporization is carried out either in metal containers(boats of tungsten, molybdenum or tantalum plate) which are heateddirectly by passing current through, or by bombardment with electronbeams.

In the case of the sputtering method or cathode atomisation, a gasdischarge (plasma) is ignited between the carrier and the coatingmaterial, which is in the form of plates (target). The coating materialis bombarded with high-energy ions from the plasma, for example argonions, and, as a result, is removed and atomised. The atoms or moleculesof the atomised coating material are deposited on the carrier and formthe desired thin layer.

Metals or alloys are especially suitable for the sputtering method. Theycan be atomised at a high rate, especially in the so-called DC magnetronmethod. Compounds such as oxides or suboxides or mixtures of oxides mayalso be atomised by using high-frequency sputtering. The chemicalcomposition of the layers is governed by the composition of the coatingmaterial (target) but may also be influenced by additions to the gasforming the plasma. In particular, oxide or nitrite layers are producedby adding oxygen or nitrogen to the gas space (see, for example, U.S.Pat. No. 5,440,446 and EP-A-0 733 919).

Preference is given to the use as vaporizers of resistance-heatedvaporizers, vaporizers heated by electron beams, inductively heatedvaporizers or arc-operated vaporizers.

In order to simplify separation, the carrier material should have asmooth or structured surface. Especially suitable carrier materials havebeen found to be a polyimide film or a metal foil or a combination ofthose materials. Preference is given to the carrier material being inthe form of a circulating belt, as described in U.S. Pat. No. 6,270,840,so that continuous production of material is made possible.

The separating agent condensed onto the carrier may be a coating, apolymer, such as a (thermoplastic) polymer described, for example inU.S. Pat. No. 6,398,999, e.g. acrylic or styrene polymers or mixturesthereof, an organic substance soluble in organic solvents or in waterand vaporizable in vacuo, such as anthracene, anthraquinone,acetamidophenol, acetylsalicylic acid, camphoric anhydride,benzimidazole, benzene-1,2,4-tricarboxylic acid,biphenyl-2,2-dicarboxylic acid, bis(4-hydroxyphenyl)sulfone,dihydroxyanthraquinone, hydantoin, 3-hydroxybenzoic acid,8-hydroxyquinoline-5-sulfonic acid monohydrate, 4-hydroxycoumarin,7-hydroxycoumarin, 3-hydroxynaphthalene-2-carboxylic acid, isophthalicacid, 4,4-methylene-bis-3-hydroxynaphthalene-2-carboxylic acid,naphthalene-1,8-dicarboxylic anhydride, phthalimide and its potassiumsalt, phenolphthalein, phenothiazine, saccharin and its salts,tetraphenylmethane, triphenylene, triphenylmethanol or a mixture of atleast two of those substances. The separating agent is preferably awater-soluble inorganic salt vaporizable in vacuo (see, for example, DE198 44 357), such as sodium chloride, potassium chloride, lithiumchloride, sodium fluoride, potassium fluoride, lithium fluoride, calciumfluoride, sodium aluminium fluoride or disodium tetraborate.

Preferred embodying examples of the invention will be described ingreater detail hereinbelow.

In a preferred embodying example of the process according to theinvention, the following are applied one after the other in vacuo,preferably in the pressure range from 1 to 10⁻³ Pa, by thermalvaporization according to the PVD method:

-   -   a separating agent layer and    -   a mixed layer, arranged on top of the separating agent, which        layer comprises the metal together with a freely selectable        proportion of SiOz introduced by simultaneous vaporization from        a further source or from the same source.

In the process according to the invention, it is, in principle, possibleto use any inorganic metal that reacts, during calcination, with theSiO_(z) present in the mixed layer. Preference is given to nickel, iron,cobalt, silver, chromium, zirconium, niobium, molybdenum, vanadium,titanium or alloys thereof, such as chromium-nickel, iron-nickel,iron-chromium and nickel-cobalt; special preference is given to the useof aluminium. Vaporization of alloys is advantageously carried out fromseparate sources having the required molar ratio.

An especially preferred embodiment of the present invention is aimed atthe production of SiO_(y)/Al flakes wherein 0.70≦y≦1.8, especially1.0≦y≦1.8:

In detail, a salt, for example NaCl, followed by a layer of siliconsuboxide (SiO_(y)) and aluminium are vapor-deposited onto a carrier,which may be a continuous metal belt, passing by way of the vaporizersunder a vacuum of >0.5 Pa. The mixed layer of silicon suboxide (SiO_(y))and aluminium is obtained by means of two vaporizers, each of which ischarged with one of the two materials and the vapor cones of whichoverlap, the metal being admixed in proportions of from 1 to 50 mol % ofthe mixed layer. The vapor-deposited thicknesses of separating agent(especially salt) are about from 20 to 100 nm, preferably from 30 to 60nm, while those of the mixed layer are, depending on the use for whichthe product is intended, from 10 to 1000 nm. On its further course, thebelt-form carrier, which is closed to form a loop, runs through dynamicvacuum lock chambers of known mode of construction (cf. U.S. Pat. No.6,270,840) into a region of from 1 to 5×10⁴ Pa pressure, preferably from600 to 10⁹ Pa pressure, and especially from 10³ to 5×10³ Pa pressure,where it is immersed in a dissolution bath. The temperature of thesolvent therein should be so selected that its vapor pressure is in theindicated pressure range. With mechanical assistance, the separatingagent layer rapidly dissolves and the product layer breaks up intoflakes, which are then present in the solvent in the form of asuspension. In a preferred embodiment, NaCl is used as the separatingagent of the separating agent layer, the NaCl dissolving in water. Onits further course, the belt is dried and freed from any contaminantsstill adhering to it. It runs through a second group of dynamic vacuumlock chambers back into the vaporization chamber, where the process ofcoating with separating agent and mixed layer of SiO_(y)/separatingagent is repeated.

The suspension then present, comprising product structures, solvent, andthe separating agent dissolved therein, is then separated in a furtheroperation in accordance with a known technique. For that purpose, theproduct structures are first concentrated in the liquid and rinsedseveral times with fresh solvent in order to wash out the dissolvedseparating agent. The product, in the form of a solid that is still wet,is then separated off by filtration, sedimentation, centrifugation,decanting or evaporation.

In accordance with a further preferred embodying example, the followingare applied one after the other in vacuo, preferably in the pressurerange from 1 to 10⁻³ Pa, by thermal vaporization according to the PVDmethod:

-   -   a separating agent layer    -   an SiO_(y) layer on top of the separating agent,    -   a mixed layer, arranged on top of the SiO_(y) layer, which layer        comprises aluminium together with a freely selectable proportion        of SiO_(z) introduced by simultaneous vaporization from a        further source or from the same source, and    -   an SiO_(y) layer on top of the mixed layer.

The SiO_(1.00-1.8) layer is formed preferably from silicon monoxidevapor produced in the vaporizer by reaction of a mixture of Si and SiO₂at temperatures of more than 1300° C. The SiO_(0.70-0.99) layer isformed preferably by evaporating silicon monoxide containing silicon inan amount up to 20% by weight at temperatures of more than 1300° C.

If, under industrial vacuums of a few 10⁻² Pa, Si is vaporized insteadof SiO, silicon oxides that have a less-than-equimolar oxygen contentare obtained, that is to say SiO_(x) wherein 0.03≦×≦0.95, especially0.05≦×≦0.5.

The thickness of each SiO_(y) layer in that embodiment varies from 10 to1000 nm. The preferred thickness is dependent upon the desired color. AnSiO_(z) layer thickness greater than about 500 nm results in mattcolors.

Further preferred subject-matter of the present invention consists ofthe particles obtainable by the process described hereinbefore andhaving the following layer structure: SiO_(y)/(mixed layer of SiO_(y)and Al=core)/SiO_(y), which may be calcined in a non-oxidativeatmosphere. Calcination of those flakes is carried out under aprotective gas atmosphere, for example helium or argon, whereappropriate under reduced pressure (<0.93 10⁵ Pa ), at a temperature ofmore than 600° C., preferably in the range from 700 to 1100C., for morethan 10 minutes, preferably more than two hours.

After calcination, the product can be subjected to oxidative heattreatment. Known methods are available for that purpose. Air or someother oxygen-containing gas is passed through the plane-parallelstructures, which are in the form of loose material or in a fluidisedbed, at a temperature of more than 200° C., preferably more than 400° C.and especially from 500 to 1000° C. The product can then be brought tothe desired particle size by means of ultrasound or by mechanical meansusing high-speed stirrers in a liquid medium, or after drying thefragments in an air-jet mill having a rotary classifier, or means ofgrinding or air-sieving and delivered for further use.

For the further processing of the flakes coated with SiO_(y) differentvariants are possible:

Variant (1) (TiO₂/SiO_(z)/core′/SiO_(z)/TiO₂, Wherein Core′ is a LayerObtained by Calcination of a Layer Consisting of SiO_(y) and Al):

The SiO_(y)-coated platelets (SiO_(y)/(mixed layer of SiO_(y) andAl=core)/SiO_(y)) are calcined in a non-oxidizing gaseous atmosphere ata temperature above 600° C., preferably in the range of from 700 to1100° C. for more then 10 minutes, preferably for several hours. Thecalcination is conducted in a non-oxidizing gaseous atmosphere, such as,for example, Ar and/or He, wherein Ar is preferred, optionally underreduced pressure, preferably a pressure of less than 700 Torr (0,933310⁵ N/m²).

The obtained platelets can then be subjected to oxidative heattreatment. For example, air or some other oxygen-containing gas ispassed through the platelets, which are in the form of loose material orin a fluidized bed, at a temperature of more than 200° C., preferablymore than 400° C. and especially from 500 to 1000° C., wherein SiO_(y)is oxidized to SiO_(z).

The TiO₂ coating can easily be applied to the SiO_(y)-coated metalplatelets by physical, or chemical vapor deposition processes, or by wetchemical coating processes.

For the purpose of coating, the substrate particles are suspended inwater and one or more hydrolysable titanium salts are added at a pHsuitable for the hydrolysis, which is so selected that the metal oxidesor metal oxide hydrates are precipitated directly onto the particleswithout subsidiary precipitation occurring. The pH is usually keptconstant by simultaneously metering in a base. The pigments are thenseparated off, washed, dried and, where appropriate, calcined, it beingpossible to optimize the calcining temperature with respect to thecoating in question. If desired, after individual coatings have beenapplied, the pigments can be separated off, dried and, whereappropriate, calcined, and then again re-suspended for the purpose ofprecipitating further layers.

In accordance with an embodiment of the present invention, the methoddescribed in U.S. Pat. No. 3,553,001 is used for application of thetitanium dioxide layers.

An aqueous titanium salt solution is slowly added to a suspension of thematerial being coated, which suspension has been heated to about 50-100°C., especially 70-80° C., and a substantially constant pH value of aboutfrom 0.5 to 5, especially about from 1.2 to 2.5, is maintained bysimultaneously metering in a base such as, for example, aqueous ammoniasolution or aqueous alkali metal hydroxide solution. As soon as thedesired layer thickness of precipitated TiO₂ has been achieved, theaddition of titanium salt solution and base is stopped.

This method, also referred to as a titration method, is distinguished bythe fact that an excess of titanium salt is avoided. That is achieved byfeeding in for hydrolysis, per unit time, only that amount which isnecessary for even coating with the hydrated TiO₂ and which can be takenup per unit time by the available surface of the particles being coated.In principle, the anatase form of TiO₂ forms on the surface of thestarting pigment. By adding small amounts of SnO₂, however, it ispossible to force the rutile structure to be formed. For example, asdescribed in WO 93/08237, tin dioxide can be deposited before titaniumdioxide precipitation and the product coated with titanium dioxide canbe calcined at from 800 to 900° C.

It is possible for the weathering resistance to be increased by means ofan additional coating, which at the same time causes an optimaladaptation to the binder system (EP-A-268918 and EP-A-632109).

Variant (2) (TiO₂/layer (E)/SiO_(z)/core′/SiO_(z)/layer (E)/TiO₂:

As described above the SiO_(y)-coated platelets (SiO_(y)/(mixed layer ofSiO_(y) and Al=core)/SiO_(y)) are coated with TiO₂ and then calcined ina non-oxidizing atmosphere. In this way an additional layer (E) isproduced besides the layer (a), which is formed by calcination ofTiO₂/SiO_(y). It is assumed that calcining TiO₂/SiO_(y) in anon-oxidizing atmosphere produces an intermediate layer that causes achange in the refractive index. However, the possibility that theintermediate layer is not a continuous layer and that, rather, onlyindividual regions at the interface of TiO₂ and SiO_(y) undergo aconversion that causes a change in the refractive index cannot be ruledout. It is further assumed that the change in the refractive index isdue to the reduction of TiO₂ by SiO_(y).

The principle according to the invention is based, therefore, onproducing, by reduction of TiO₂ with SiO_(y), an intermediate layer thatcauses a change in the refractive index.TiO₂+SiO_(y)→SiO_(y+a)+TiO_(2−a)

Accordingly, further preferred embodiments of the present invention aredirected to pigments having a layer structure,TiO₂/SiO_(z)/core/SiO_(z)/TiO₂, wherein the SiO_(z) layer is onlypresent on the plane-parallel faces, but not the side faces and the TiO₂layer is applied to the whole surface; as well as pigments having alayer structure, TiO₂/layer (E)/SiO_(z)/core/SiO_(z)/layer (E)/TiO₂,wherein the SiO_(z) layer and the layer (E) is only present on theplane-parallel faces, but not the side faces and the TiO₂ layer isapplied to the whole surface.

Alternatively, pigments can be obtained by the following methods:

Variant (3): calcination in a non-oxidizing atmosphere (→layer (a)),coating of the obtained pigments with TiO₂(TiO₂/SiO_(y)/core′/SiO_(y)/TiO₂) and optionally calcination in thepresence of oxygen (SiO_(y)→SiO_(z)) (TiO₂/SiO_(z)/core′/SiO_(z)/TiO₂).

Variant (4): calcination in a non-oxidizing atmosphere (→layer (a)),coating of the obtained pigments with TiO₂, calcination in anon-oxidizing atmosphere (→layer (E)) (TiO₂/layer(E)/SiO_(y)/core′/SiO_(y)/layer (E)/TiO₂) and optionally calcination inthe presence of oxygen (SiO_(y)→SiO_(z)) (TiO₂/layer(E)/SiO_(z)/core′/SiO_(z)/layer (E)/TiO₂).

If desired, the TiO₂ can be reduced to titanium suboxides by usualmethods, as described, for example in U.S. Pat. No. 4,948,631, JPH4-20031, DE-A-19618562 and DE-A-198 43 014).

It is possible to obtain pigments that are more intense in color andmore transparent by applying, on top of the TiO₂ layer, a metal oxide of“low” refractive index, that is to say a refractive index smaller thanabout 1.65, such as SiO₂, Al₂O₃, AlOOH, B₂O₃ or a mixture thereof,preferably SiO₂, and applying a further Fe₂O₃ and/or TiO₂ layer on topof the latter layer. Such multi-coated interference pigments comprisinga silicon oxide substrate and alternating metal oxide layers of withhigh and low refractive index can be prepared in analogy to theprocesses described in WO98/53011 and WO99/20695.

Where appropriate, an SiO₂ (protective) layer can be applied on top ofthe titanium dioxide layer, for which the following method may be used:A soda water glass solution is metered in to a suspension of thematerial being coated, which suspension has been heated to about 50-100°C., especially 70-80° C. The pH is maintained at from 4 to 10,preferably from 6.5 to 8.5, by simultaneously adding 10% hydrochloricacid. After addition of the water glass solution, stirring is carriedout for 30 minutes.

It is, in addition, possible to modify the powder color of the pigmentby applying further layers such as, for example, colored metal oxides orBerlin Blue, compounds of transition metals, e.g. Fe, Cu, Ni, Co, Cr, ororganic compounds such as dyes or color lakes.

It is furthermore possible to subject the finished pigment to subsequentcoating or subsequent treatment which further increases the light,weather and chemical stability or which facilitates handling of thepigment, especially its incorporation into various media. For example,the procedures described in DE-A-22 15 191, DE-A-31 51 354, DE-A-32 35017, DE-A-33 34 598, DE-A-4030727, EP-A-649886, WO97/29059, WO99/57204,and U.S. Pat. No. 5,759,255 are suitable as subsequent treatment orsubsequent coating.

In addition, the pigment according to the invention can also be coatedwith poorly soluble, firmly adhering, inorganic or organic colorants.Preference is given to the use of color lakes and, especially, aluminumcolor lakes. For that purpose an aluminum hydroxide layer isprecipitated, which is, in a second step, laced by using a color lake(DE-A-24 29 762 and DE 29 28 287).

Furthermore, the pigment according to the invention may also have anadditional coating with complex salt pigments, especially cyan ferratecomplexes (EP-A-141 173 and DE-A-23 13 332).

After the SiO_(y)-coated flakes (SiO_(y)/(mixed layer of SiO_(y) andAl=core)/SiO_(y)) have been calcined, as described in Variant (1), in anon-oxidizing gaseous atmosphere at a temperature above 600° C.,preferably in the range of from 700 to 1100° C. for more than 10minutes, preferably for several hours, they can also be caused to reactin a gas-tight reactor heatable to a maximum of about 1500° C.,preferably in the form of loose material, with a carbon-containing gasselected from alkynes, for example acetylene, alkenes, for examplemethane, alkenes, aromatic compounds or the like, and mixtures thereofoptionally in admixture with an oxygen containing compound, such as, forexample, aldehydes, ketones, water, carbon monoxide, carbon dioxide orthe like, or mixtures thereof, at from 500 to 1500° C., preferably from500 to 1000° C., and advantageously with the exclusion of oxygen. Inorder to temper the reaction, an inert gas, for example argon or helium,may be admixed with the carbon-containing gas (WO03/68868).

At pressures of less than about 1 Pa the reaction generally alsoproceeds too slowly whereas, especially when the carbon-containing gasesare less reactive or are highly diluted with inert gas, it is perfectlypossible to operate at pressures of up to about 4000 bar, as areroutinely used, for example, in HIP (“hot isocratic pressing”) systems.

In such carbonization, it is possible for all of the SiO_(y) to bereacted to form SiC; preferably from 5 to 90% by weight of the SiO_(y)are reacted to form SiC. The temperature for the process of conversionof SiO_(y) to SiC is from 500° to 1500° C., preferably from 500° C. to1000° C., with a process duration of from about one hour to about twentyhours. The reaction takes place starting from the surface of theplane-parallel structures and accordingly results in a gradient ratherthan a sharp transition. This means that, in that embodiment, theSiC-containing layer consists of (SiO_(y))_(a) and (SiC)_(b), wherein0≦a≦1 and 0≦b≦1, with b being 1 and a being 0 close to the surface ofthe pigment and the amount of SiC approaching 0 close to the boundarywith the SiO_(y) substrate. The SiO_(y) structures are sufficientlyporous for such a reaction not to be limited only to the uppermost layerof SiO_(y) molecules.

According to this process variant pigments having the following layerstructure, SiC/SiO_(y)/core′/SiO_(y)/SiC, can be obtained, which can beconverted to pigments having the following layer structure,SiC/SiO_(z)/core′/SiO_(z)/SiC, by calcination in the presence of oxygen.The pigments obtained by this process are new and are a further subjectof the present invention.

Instead of a layer of a metal oxide having a high index of refractionU.S. Pat. No. 6,524,381 materials, such as diamond-like carbon andamorphous carbon, can be deposited by plasma-assisted vacuum methods(using vibrating conveyors, rotating drum coaters, oscillatory drumcoaters, and free-fall chambers) as described, for example in U.S. Pat.No. 6,524,381, on the SiO_(z)-coated substrates.

Consequently, the present invention also relates to plane-parallelstructures (pigments) based on SiO_(z)/core′/SiO_(z) substrates havingon their surface a carbon layer especially a diamond-like carbon layerhaving a thickness of 5 to 150 nm, especially 20 to 50 nm.

In the method described, for example, in U.S. Pat. No. 6,015,597,diamond-like network (DLN) coatings are deposited onto particles fromcarbon-containing gases, such as, for example, acetylene, methane,butadiene and mixtures of these and optionally Ar, and optionally gasescontaining additional components by plasma deposition. Deposition occursat reduced pressures (relative to atmospheric pressure) and in acontrolled environment. A carbon rich plasma is created in a reactionchamber by applying an electric field to a carbon-containing gas.Particles to be coated are held in a vessel or container in the reactorand are agitated while in proximity to the plasma. Species within theplasma react on the particle surface to form covalent bonds, resultingin DLN on the surface of the particles.

The term “diamond-like network” (DLN) refers to amorphous films orcoatings comprised of carbon and optionally comprising one or moreadditional components selected from the group consisting of hydrogen,nitrogen, oxygen, fluorine, silicon, sulfur, titanium, and copper. Thediamond-like networks comprise approximately 30 to 100 atomic percentcarbon, with optional additional components making up the remainder.

The platelet-shaped Al/SiO_(z) particles may be used, for example, assubstrates for effect pigments. The further layers necessary forinterference effects may be applied in accordance with customarymethods, already described in greater detail hereinbefore, that areknown for effect pigments having mica, SiO₂ or Al₂O₃ cores.

The pigments according to the invention are distinguished by high glossand a very uniform thickness, as a result of which very high colorpurity and color strength are achieved. The pigments according to theinvention can be used for all customary purposes, for example forcoloring textiles, polymers in the mass, coatings (including effectfinishes, including those for the automotive sector), glazes forceramics and glass, and printing inks (including security printing), andalso, for example, for applications in cosmetics and in ink-jetprinting. Such applications are known from reference works, for example“Industrielle Organische Pigmente” (W. Herbst and K. Hunger, VCHVerlagsgesellschaft mbH, Weinheim/N.Y., 2nd, completely revised edition,1995).

Metallic or non-metallic, inorganic platelet-shaped particles orpigments are effect pigments, (especially metal effect pigments orinterference pigments), that is to say, pigments that, besides impartingcolor to an application medium, impart additional properties, forexample angle dependency of the color (flop), lustre (not surface gloss)or texture. On metal effect pigments, substantially oriented reflectionoccurs at directionally oriented pigment particles. In the case ofinterference pigments, the color-imparting effect is due to thephenomenon of interference of light in thin, highly refractive layers.

When the pigments according to the invention are interference pigments(effect pigments), they are goniochromatic and result in brilliant,highly saturated (lustrous) colors. They are accordingly very especiallysuitable for combination with conventional, transparent pigments, forexample organic pigments such as, for example, diketopyrrolopyrroles,quinacridones, dioxazines, perylenes, isoindolinones etc., it beingpossible for the transparent pigment to have a similar color to theeffect pigment. Especially interesting combination effects are obtained,however, in analogy to, for example, EP 388 932 or EP 402 943, when thecolor of the transparent pigment and that of the effect pigment arecomplementary.

The pigments according to the invention can be used with excellentresults for pigmenting high molecular weight organic material.

The high molecular weight organic material for the pigmenting of whichthe pigments or pigment compositions according to the invention may beused may be of natural or synthetic origin. High molecular weightorganic materials usually have molecular weights of about from 10³ to10⁸ g/mol or even more. They may be, for example, natural resins, dryingoils, rubber or casein, or natural substances derived therefrom, such aschlorinated rubber, oil-modified alkyd resins, viscose, cellulose ethersor esters, such as ethylcellulose, cellulose acetate, cellulosepropionate, cellulose acetobutyrate or nitrocellulose, but especiallytotally synthetic organic polymers (thermosetting plastics andthermoplastics), as are obtained by polymerisation, polycondensation orpolyaddition. From the class of the polymerisation resins there may bementioned, especially, polyolefins, such as polyethylene, polypropyleneor polyisobutylene, and also substituted polyolefins, such aspolymerisation products of vinyl chloride, vinyl acetate, styrene,acrylonitrile, acrylic acid esters, methacrylic acid esters orbutadiene, and also copolymerisation products of the said monomers, suchas especially ABS or EVA.

From the series of the polyaddition resins and polycondensation resinsthere may be mentioned, for example, condensation products offormaldehyde with phenols, so-called phenoplasts, and condensationproducts of formaldehyde with urea, thiourea or melamine, so-calledaminoplasts, and the polyesters used as coating resins, eithersaturated, such as alkyd resins, or unsaturated, such as maleate resins;also linear polyesters and polyamides, polyurethanes or silicones.

The said high molecular weight compounds may be present singly or inmixtures, in the form of plastic masses or melts. They may also bepresent in the form of their monomers or in the polymerised state indissolved form as film-formers or binders for coatings or printing inks,such as, for example, boiled linseed oil, nitrocellulose, alkyd resins,melamine resins and urea-formaldehyde resins or acrylic resins.

Depending on the intended purpose, it has proved advantageous to use thepigments or pigment compositions according to the invention as toners orin the form of preparations. Depending on the conditioning method orintended application, it may be advantageous to add certain amounts oftexture-improving agents to the pigment before or after the conditioningprocess, provided that this has no adverse effect on use of the effectpigments for colouring high molecular weight organic materials,especially polyethylene. Suitable agents are, especially, fatty acidscontaining at least 18 carbon atoms, for example stearic or behenicacid, or amides or metal salts thereof, especially magnesium salts, andalso plasticisers, waxes, resin acids, such as abietic acid, rosin soap,alkylphenols or aliphatic alcohols, such as stearyl alcohol, oraliphatic 1,2-dihydroxy compounds containing from 8 to 22 carbon atoms,such as 1,2-dodecanediol, and also modified colophonium maleate resinsor fumaric acid colophonium resins. The texture-improving agents areadded in amounts of preferably from 0.1 to 30% by weight, especiallyfrom 2 to 15% by weight, based on the end product.

The pigments according to the invention can be added in any tinctoriallyeffective amount to the high molecular weight organic material beingpigmented. A pigmented substance composition comprising a high molecularweight organic material and from 0.01 to 80% by weight, preferably from0.1 to 30% by weight, based on the high molecular weight organicmaterial; of an pigment according to the invention is advantageous.Concentrations of from 1 to 20% by weight, especially of about 10% byweight, can often be used in practice. High concentrations, for examplethose above 30% by weight, are usually in the form of concentrates(“masterbatches”) which can be used as colorants for producing pigmentedmaterials having a relatively low pigment content, the pigmentsaccording to the invention having an extraordinarily low viscosity incustomary formulations so that they can still be processed well.

For the purpose of pigmenting organic materials, the pigments accordingto the invention may be used singly. It is, however, also possible, inorder to achieve different hues or color effects, to add any desiredamounts of other color-imparting constituents, such as white, colored,black or effect pigments, to the high molecular weight organicsubstances in addition to the effect pigments according to theinvention. When colored pigments are used in admixture with the effectpigments according to the invention, the total amount is preferably from0.1 to 10% by weight, based on the high molecular weight organicmaterial. Especially high goniochromicity is provided by the preferredcombination of an effect pigment according to the invention with acolored pigment of another color, especially of a complementary color,with colorations made using the effect pigment and colorations madeusing the colored pigment having, at a measurement angle of 10°, adifference in hue (ΔH*) of from 20 to 340, especially from 150 to 210.

Preferably, the effect pigments according to the invention are combinedwith transparent colored pigments, it being possible for the transparentcolored pigments to be present either in the same medium as the effectpigments according to the invention or in a neighbouring medium. Anexample of an arrangement in which the effect pigment and the coloredpigment are advantageously present in neighbouring media is amulti-layer effect coating.

The pigmenting of high molecular weight organic substances with thepigments according to the invention is carried out, for example, byadmixing such a pigment, where appropriate in the form of a masterbatch,with the substrates using roll mills or mixing or grinding apparatuses.The pigmented material is then brought into the desired final form usingmethods known per se, such as calendering, compression moulding,extrusion, coating, pouring or injection moulding. Any additivescustomary in the plastics industry, such as plasticisers, fillers orstabilisers, can be added to the polymer, in customary amounts, beforeor after incorporation of the pigment. In particular, in order toproduce non-rigid shaped articles or to reduce their brittleness, it isdesirable to add plasticisers, for example esters of phosphoric acid,phthalic acid or sebacic acid, to the high molecular weight compoundsprior to shaping.

For pigmenting coatings and printing inks, the high molecular weightorganic materials and the pigments according to the invention, whereappropriate together with customary additives such as, for example,fillers, other pigments, siccatives or plasticisers, are finelydispersed or dissolved in the same organic solvent or solvent mixture,it being possible for the individual components to be dissolved ordispersed separately or for a number of components to be dissolved ordispersed together, and only thereafter for all the components to bebrought together.

Dispersing a pigment according to the invention in the high molecularweight organic material being pigmented, and processing a pigmentcomposition according to the invention, are preferably carried outsubject to conditions under which only relatively weak shear forcesoccur so that the effect pigment is not broken up into smaller portions.

The colorations obtained, for example in plastics, coatings or printinginks, especially in coatings or printing inks, more especially incoatings, are distinguished by excellent properties, especially byextremely high saturation, outstanding fastness properties and highgoniochromicity.

When the high molecular weight material being pigmented is a coating, itis especially a speciality coating, very especially an automotivefinish.

The pigments according to the invention are also suitable for making-upthe lips or the skin and for colouring the hair or the nails.

The invention accordingly relates also to a cosmetic preparation orformulation comprising from 0.0001 to 90% by weight of thesilicon/silicon oxide flakes and/or of a pigment according to theinvention and from 10 to 99.9999% of a cosmetically suitable carriermaterial, based on the total weight of the cosmetic preparation orformulation.

Such cosmetic preparations or formulations are, for example, lipsticks,blushers, foundations, nail varnishes and hair shampoos.

The pigments may be used singly or in the form of mixtures. It is, inaddition, possible to use pigments according to the invention togetherwith other pigments and/or colorants, for example in combinations asdescribed hereinbefore or as known in cosmetic preparations.

The cosmetic preparations and formulations according to the inventionpreferably contain the pigment according to the invention in an amountfrom 0.005 to 50% by weight, based on the total weight of thepreparation.

Suitable carrier materials for the cosmetic preparations andformulations according to the invention include the customary materialsused in such compositions.

The cosmetic preparations and formulations according to the inventionmay be in the form of, for example, sticks, ointments, creams,emulsions, suspensions, dispersions, powders or solutions. They are, forexample, lipsticks, mascara preparations, blushers, eye-shadows,foundations, eyeliners, powder or nail varnishes.

If the preparations are in the form of sticks, for example lipsticks,eye-shadows, blushers or foundations, the preparations consist for aconsiderable part of fatty components, which may consist of one or morewaxes, for example ozokerite, lanolin, lanolin alcohol, hydrogenatedlanolin, acetylated lanolin, lanolin wax, beeswax, candelilla wax,microcrystalline wax, carnauba wax, cetyl alcohol, stearyl alcohol,cocoa butter, lanolin fatty acids, petrolatum, petroleum jelly, mono-,di- or tri-glycerides or fatty esters thereof that are solid at 25° C.,silicone waxes, such as methyloctadecane-oxypolysiloxane andpoly(dimethylsiloxy)-stearoxysiloxane, stearic acid monoethanolamine,colophane and derivatives thereof, such as glycol abietates and glycerolabietates, hydrogenated oils that are solid at 25° C., sugar glyceridesand oleates, myristates, lanolates, stearates and dihydroxystearates ofcalcium, magnesium, zirconium and aluminium.

The fatty component may also consist of a mixture of at least one waxand at least one oil, in which case the following oils, for example, aresuitable: paraffin oil, purcelline oil, perhydrosqualene, sweet almondoil, avocado oil, calophyllum oil, castor oil, sesame oil, jojoba oil,mineral oils having a boiling point of about from 310 to 410° C.,silicone oils, such as dimethylpolysiloxane, linoleyl alcohol, linolenylalcohol, oleyl alcohol, cereal grain oils, such as wheatgerm oil,isopropyl lanolate, isopropyl palmitate, isopropyl myristate, butylmyristate, cetyl myristate, hexadecyl stearate, butyl stearate, decyloleate, acetyl glycerides, octanoates and decanoates of alcohols andpolyalcohols, for example of glycol and glycerol, ricinoleates ofalcohols and polyalcohols, for example of cetyl alcohol, isostearylalcohol, isocetyl lanolate, isopropyl adipate, hexyl laurate and octyldodecanol.

The fatty components in such preparations in the form of sticks maygenerally constitute up to 99.91% by weight of the total weight of thepreparation.

The cosmetic preparations and formulations according to the inventionmay additionally comprise further constituents, such as, for example,glycols, polyethylene glycols, polypropylene glycols, monoalkanolamides,non-colored polymeric, inorganic or organic fillers, preservatives, UVfilters or other adjuvants and additives customary in cosmetics, forexample a natural or synthetic or partially synthetic di- ortri-glyceride, a mineral oil, a silicone oil, a wax, a fatty alcohol, aGuerbet alcohol or ester thereof, a lipophilic functional cosmeticactive ingredient, including sun-protection filters, or a mixture ofsuch substances.

A lipophilic functional cosmetic active ingredient suitable for skincosmetics, an active ingredient composition or an active ingredientextract is an ingredient or a mixture of ingredients that is approvedfor dermal or topical application. The following may be mentioned by wayof example:

-   -   active ingredients having a cleansing action on the skin surface        and the hair; these include all substances that serve to cleanse        the skin, such as oils, soaps, synthetic detergents and solid        substances;    -   active ingredients having a deodorising and        perspiration-inhibiting action: they include antiperspirants        based on aluminium salts or zinc salts, deodorants comprising        bactericidal or bacteriostatic deodorising substances, for        example triclosan, hexachlorophene, alcohols and cationic        substances, such as, for example, quaternary ammonium salts, and        odour absorbers, for example ®Grillocin (combination of zinc        ricinoleate and various additives) or triethyl citrate        (optionally in combination with an antioxidant, such as, for        example, butyl hydroxytoluene) or ion-exchange resins;    -   active ingredients that offer protection against sunlight (UV        filters): suitable active ingredients are filter substances        (sunscreens) that are able to absorb UV radiation from sunlight        and convert it into heat; depending on the desired action, the        following light-protection agents are preferred:        light-protection agents that selectively absorb sunburn-causing        high-energy UV radiation in the range of approximately from 280        to 315 nm (UV-B absorbers) and transmit the longer-wavelength        range of, for example, from 315 to 400 nm (UV-A range), as well        as light-protection agents that absorb only the        longer-wavelength radiation of the UV-A range of from 315 to 400        nm (UV-A absorbers); suitable light-protection agents are, for        example, organic UV absorbers from the class of the        p-aminobenzoic acid derivatives, salicylic acid derivatives,        benzophenone derivatives, dibenzoylmethane derivatives, diphenyl        acrylate derivatives, benzofuran derivatives, polymeric UV        absorbers comprising one or more organosilicon radicals,        cinnamic acid derivatives, camphor derivatives,        trianilino-s-triazine derivatives, phenyl-benzimidazolesulfonic        acid and salts thereof, menthyl anthranilates, benzotriazole        derivatives, and/or an inorganic micropigment selected from        aluminium oxide- or silicon dioxide-coated TiO₂, zinc oxide or        mica;    -   active ingredients against insects (repellents) are agents that        are intended to prevent insects from touching the skin and        becoming active there; they drive insects away and evaporate        slowly; the most frequently used repellent is diethyl toluamide        (DEET); other common repellents will be found, for example, in        “Pflegekosmetik” (W. Raab and U. Kindl, Gustav-Fischer-Verlag        Stuttgart/New York,1991) on page 161;    -   active ingredients for protection against chemical and        mechanical influences: these include all substances that form a        barrier between the skin and external harmful substances, such        as, for example, paraffin oils, silicone oils, vegetable oils,        PCL products and lanolin for protection against aqueous        solutions, film-forming agents, such as sodium alginate,        triethanolamine alginate, polyacrylates, polyvinyl alcohol or        cellulose ethers for protection against the effect of organic        solvents, or substances based on mineral oils, vegetable oils or        silicone oils as “lubricants” for protection against severe        mechanical stresses on the skin;    -   moisturising substances: the following substances, for example,        are used as moisture-controlling agents (moisturisers): sodium        lactate, urea, alcohols, sorbitol, glycerol, propylene glycol,        collagen, elastin and hyaluronic acid;    -   active ingredients having a keratoplastic effect: benzoyl        peroxide, retinoic acid, colloidal sulfur and resorcinol;    -   antimicrobial agents, such as, for example, triclosan or        quaternary ammonium compounds;    -   oily or oil-soluble vitamins or vitamin derivatives that can be        applied dermally: for example vitamin A (retinol in the form of        the free acid or derivatives thereof), panthenol, pantothenic        acid, folio acid, and combinations thereof, vitamin E        (tocopherol), vitamin F; essential fatty acids; or niacinamide        (nicotinic acid amide);    -   vitamin-based placenta extracts: active ingredient compositions        comprising especially vitamins A, C, E, B₁, B₂, B₆, B₁₂, folic        acid and biotin, amino acids and enzymes as well as compounds of        the trace elements magnesium, silicon, phosphorus, calcium,        manganese, iron or copper;    -   skin repair complexes: obtainable from inactivated and        disintegrated cultures of bacteria of the bifidus group;    -   plants and plant extracts: for example arnica, aloe, beard        lichen, ivy, stinging nettle, ginseng, henna, camomile,        marigold, rosemary, sage, horsetail or thyme;    -   animal extracts: for example royal jelly, propolis, proteins or        thymus extracts;    -   cosmetic oils that can be applied dermally: neutral oils of the        Miglyol 812 type, apricot kernel oil, avocado oil, babassu oil,        cottonseed oil, borage oil, thistle oil, groundnut oil,        gamma-oryzanol, rosehip-seed oil, hemp oil, hazelnut oil,        blackcurrant-seed oil, jojoba oil, cherry-stone oil, salmon oil,        linseed oil, cornseed oil, macadamia nut oil, almond oil,        evening primrose oil, mink oil, olive oil, pecan nut oil, peach        kernel oil, pistachio nut oil, rape oil, rice-seed oil, castor        oil, safflower oil, sesame oil, soybean oil, sunflower oil, tea        tree oil, grapeseed oil or wheatgerm oil.

The preparations in stick form are preferably anhydrous but may incertain cases comprise a certain amount of water which, however, ingeneral does not exceed 40% by weight, based on the total weight of thecosmetic preparation.

If the cosmetic preparations and formulations according to the inventionare in the form of semi-solid products, that is to say in the form ofointments or creams, they may likewise be anhydrous or aqueous. Suchpreparations and formulations are, for example, mascaras, eyeliners,foundations, blushers, eye-shadows, or compositions for treating ringsunder the eyes.

If, on the other hand, such ointments or creams are aqueous, they areespecially emulsions of the water-in-oil type or of the oil-in-watertype that comprise, apart from the pigment, from 1 to 98.8% by weight ofthe fatty phase, from 1 to 98.8% by weight of the aqueous phase and from0.2 to 30% by weight of an emulsifier.

Such ointments and creams may also comprise further conventionaladditives, such as, for example, perfumes, antioxidants, preservatives,gel-forming agents, UV filters, colorants, pigments, pearlescent agents,non-colored polymers as well as inorganic or organic fillers.

If the preparations are in the form of a powder, they consistsubstantially of a mineral or inorganic or organic filler such as, forexample, talcum, kaolin, starch, polyethylene powder or polyamidepowder, as well as adjuvants such as binders, colorants etc.

Such preparations may likewise comprise various adjuvants conventionallyemployed in cosmetics, such as fragrances, antioxidants, preservativesetc.

If the cosmetic preparations and formulations according to the inventionare nail varnishes, they consist essentially of nitrocellulose and anatural or synthetic polymer in the form of a solution in a solventsystem, it being possible for the solution to comprise other adjuvants,for example pearlescent agents.

In that embodiment, the colored polymer is present in an amount ofapproximately from 0.1 to 5% by weight.

The cosmetic preparations and formulations according to the inventionmay also be used for coloring the hair, in which case they are used inthe form of shampoos, creams or gels that are composed of the basesubstances conventionally employed in the cosmetics industry and apigment according to the invention.

The cosmetic preparations and formulations according to the inventionare prepared in conventional manner, for example by mixing or stirringthe components together, optionally with heating so that the mixturesmelt.

The Examples that follow illustrate the invention without limiting thescope thereof. Unless otherwise indicated, percentages and parts arepercentages and parts by weight, respectively.

EXAMPLES Example 1

A flat piece of glass measuring 4×4 cm is placed, as target material, ina vacuum chamber (BAK 600, Balzers AG), in which various introducedsubstances can be vaporized using, as desired, an electron gun or Jouleheating. First, at a pressure of 1.33 10⁻² Pa, a mixed layer of metallicaluminium and SiO is built up from introduced aluminium (Joule heating,1400 to 1500° C.) and silicon oxide (electron gun), the vapor jets ofwhich overlap, at a vapor-deposition rate of 0.2 nm/second; a TiO₂ layeris then vapor-deposited (electron gun) on top of that layer fromintroduced titanium dioxide.

The layer thickness of the SiO/Al layer and the TiO₂ layer is determinedusing a micro-scanning device and the stoichiometry of the SiO layer isdetermined by ESCA. The reflection color (CIE-L*C*h) is measured underillumination with D₆₅ standard light at viewing angles of 10° and 45°.The layer thicknesses of the SiO/Al layer and the TiO₂ layer of samples1 and 2 obtained in accordance with Example 1 are given in Table 1. Thereflection colors of samples 1 and 2 at viewing angles of 10° and 45°are given in Table 2.

Example 2

Example 1 is repeated but, instead of aluminium and silicon oxide,aluminium and silicon dioxide are vaporized. The layer thicknesses ofthe SiO₂/Al layer and the TiO₂ layer of sample 3 obtained in accordancewith Example 2 are given in Table 1. The reflection colors of sample 3at viewing angles of 10° and 45° are given in Table 2.

Example 3

Example 2 is repeated but, instead of titanium dioxide, silicon dioxideis vaporized and, in addition, silicon oxide is vaporized after thesilicon dioxide. The layer thicknesses of the SiO₂/Al layer, SiO₂ layerand the SiO layer of sample 4 obtained in accordance with Example 3 aregiven in Table 1. The reflection colors of sample 4 at viewing angles of10° and 45° are given in Table 2.

In Examples 1 to 3, vaporization is so controlled that the weight ratioof aluminium to SiO and/or SiO₂ is about 50:50.

TABLE 1 Exam- Sam- ple ple Carrier 1st layer 2nd layer 3rd layer 1 1glass 30 nm Al/SiO 192 nm TiO₂ — 1 2 glass 28 nm Al/SiO 192 nm TiO₂ — 23 glass 118 nm Al/SiO₂ 192 nm TiO₂ — 3 4 glass 118 nm Al/SiO₂ 330 nmSiO₂ 50 nm SiO

TABLE 2 Viewing angle Sample [°] L* a b C* h 1 10 75.4 −33.5 −17.2 37.6207.2 1 45 69.8 −14.1 −29.2 32.5 244.3 2 10 62.7 −44.1 −23.1 49.8 207.62 45 55.8 −21.2 −36.5 42.2 239.9 3 10 99 −8.7 34.3 35.4 104.2 3 45 98−13.5 27.4 30.6 116.3 4 10 82.7 −42.2 13.7 44.3 162 4 45 78 39.3 −7 39.9349.9

Example 4

Samples 2 and 3 are heated at 650° C. under argon for 2 hours. Thereflection colours of samples 2′ and 3′ obtained in that manner, atviewing angles of 10° and 45°, are given in Table 3.

TABLE 3 Viewing angle Sample [°] L* a b C* h 2′ 10 52.5 −22.6 −11.9 25.5207.8 2′ 45 50.1 −14 −20.1 24.5 235.2 3′ 10 56.4 −33.3 11.6 35.3 160.83′ 45 57.6 −38 −6.9 38.7 190.3

1. A platelet-shaped pigment the particles of which generally have alength of from 2 μm to 5 mm, a width of from 2 μm to 2 mm and athickness of from 20 nm to 1.5 μm and also a ratio of length tothickness of at least 2:1, comprising (a) a layer obtained bycalcination in a non-oxidizing atmosphere at a temperature above 600° C.of a composite layer comprising a matrix of SiO_(z) wherein 0.03≦z≦2.0and embedded therein a metal.
 2. A platelet-shaped pigment according toclaim 1, wherein layer (a) forms the core of the pigment.
 3. Aplatelet-shaped pigment according to claim 1, comprising (b1) a SiO_(z)layer, (a) a layer obtained by calcination of a layer comprising SiO_(z)and a metal, and (b2) a SiO_(z) layer, wherein 0.03≦z≦2.0.
 4. Aplatelet-shaped pigment according to claim 2, comprising (c1) a layer ofa metal oxide of high refractive index, especially TiO₂, (b1)optionally, a SiO_(z) layer, (a) a layer obtained by calcination of alayer comprising SiO_(z) and a metal, (b2) optionally, a SiO_(z) layer,wherein 0.03≦z≦2.0, and (c2) a layer of a metal oxide of high refractiveindex, especially TiO₂; or (c1) a carbon layer, (b1) a SiO_(z) layer,(a) a layer obtained by calcination of a layer comprising SiO_(z) and ametal, (b2) a SiO_(z) layer, wherein 0.03≦z≦2.0, and (c2) a carbonlayer; or (c1) a layer comprising silicon carbide (SiC), (b1) a SiO_(z)layer, (a) a layer obtained by calcination of a layer comprising SiO_(z)and a metal, (b2) a SiO_(z) layer, wherein 0.03≦z≦2.0, and (c2) a layercomprising silicon carbide (SiC).
 5. A platelet-shaped pigment accordingto claim 1, wherein 0.03≦z≦0.95.
 6. A platelet-shaped pigment accordingto claim 1, wherein 0.95≦z≦2.0.
 7. A platelet-shaped pigment accordingto claim 1, wherein the metal is Al, Cu, Mo, V, Ag, Cr, Zr, Nb, Ni, Fe,Co, Ti or alloys thereof.
 8. A process for the production of a pigmentaccording to claim 1, comprising a) vapor-deposition of a separatingagent layer onto a carrier, b) then, simultaneous vapour-deposition of ametal and SiO_(z) wherein 0.03≦z≦2.0 onto the separating agent layer, c)dissolution of the separating agent in a solvent, d) separation of theproduct from the solvent and e) calcination in a non-oxidizingatmosphere at a temperature above 600° C. of the product.
 9. A processaccording to claim 8, wherein 1.0≦z≦1.8.
 10. A process according toclaim 9, wherein in step b) an SiO_(z)/metal layer is vapor-deposited bymeans of two separate vaporizers, one vaporizer having a chargecomprising a mixture of Si and SiO₂, SiO_(z) or a mixture thereof,wherein 1.0≦z≦1.8, and the other vaporizer having a charge of metal. 11.A platelet-shaped pigment obtained by the process according to claim 8.12. A paint, textile, ink-jet printing, cosmetic, coating, plastics orprinting ink composition or a glaze for ceramics and glass comprising apigment according to claim
 1. 13. A platelet-shaped pigment according toclaim 2, wherein 0.03≦z≦0.95.
 14. A platelet-shaped pigment according toclaim 2, wherein 0.95≦z≦2.0.
 15. A platelet-shaped pigment according toclaim 2, wherein the metal is Al, Cu, Mo, V, Ag, Cr, Zr, Nb, Ni, Fe, Co,Ti or alloys thereof.
 16. A platelet-shaped pigment according to claim3, wherein the metal is Al, Cu, Mo, V, Ag, Cr, Zr, Nb, Ni, Fe, Co, Ti oralloys thereof.
 17. A platelet-shaped pigment according to claim 4,wherein the metal is Al, Cu, Mo, V, Ag, Cr, Zr, Nb, Ni, Fe, Co, Ti oralloys thereof.
 18. A platelet-shaped pigment according to claim 1,wherein the metal is aluminium.
 19. A platelet-shaped pigment obtainedby the process according to claim
 9. 20. A paint, textile, ink-jetprinting, cosmetic, coating, plastic or printing ink composition or aglaze for ceramics and glass comprising a pigment according to claim 11.